The farm at the centre of the outbreak was today identified as the Bernard Matthews site at Holton near Halesworth, Suffolk, by trading standards officials.

A statement from the EU Commission said: "Samples from the infected establishment were immediately sent to the Community Reference Laboratory in Weybridge, which has this morning swiftly confirmed the disease to be the H5N1 strain of avian influenza.

"Further tests to characterise the virus are under way, in order to ascertain whether or not it is the Asian strain."

Restrictions have already been put in place at the farm to stop birds being moved in or out of the site, and staff were being monitored.

This is the first time that H5N1 has been found at a commercial property in the UK.

More than 30,000 birds were slaughtered after chickens near Dereham, Norfolk, tested positive in April 2006, but they were found to have the

H7 strain of the virus.

The same month a wild swan was found washed up in a harbour in the Cellardyke area of Fife, which tested positive for the H5N1 strain, but was an isolated case.

The H5N1 strain can cause the highly pathogenic form of the disease, and has led to the deaths of 164 people since 2003, mostly in Asia and the Middle East.

There are fears the version of the virus could mutate to a strain which is transmitted easily from person to person, creating a global pandemic.

The new outbreak will be top of the agenda at a meeting on Tuesday of the EU's committee of veterinary experts - senior national Government vets representing all member states.

The Department for the Environment, Food and Rural Affairs (Defra) confirmed the H5N1 outbreak after it was announced by the EU Commission, and said test results on whether the strain was similar to that found in Asia were expected later today.

A statement from the department said a protection zone of three kilometres (1.8 miles) and a surveillance zone of 10 kilometres (6.2 miles) around the premises was being enforced.

Movement restrictions are being imposed and poultry must be isolated from wild birds. The farm itself has been under restrictions since Thursday evening.

Defra also announced bird shows and pigeon racing would no longer be permitted, as the national general licence on bird gatherings had been revoked.

Wider restrictions may be imposed in the area, depending on the risks posed to poultry by this outbreak, the department warned.

Neil Parish, chairman of the European Parliament's agriculture committee, said there was no need to panic.

Mr Parish, who is the Parliament's leading member on bird flu preparations, was responsible for the contingency plans being enacted by Defra at the site.

He said: "This outbreak has been detected early and action taken swiftly to contain it.

"The EU and Defra have put in place some very stringent procedures to prevent an outbreak from spreading.

"Of course we must all be vigilant, but there is absolutely no need for panic or hysteria."

He added: "There is always a danger that an outbreak can occur at any time. What we have got to do is make sure Defra have got this under control.

"They must close it down as quickly as possible. Nothing must move, food, eggs. Everything is destroyed and nothing is moved around.

"If you can stamp it out quickly it will be OK. Nothing must be allowed to spread and we must be absolutely ruthless.

"It will drive the poultry farmers mad in the area for the short term, but it has to be done in this way."

Mr Parish, a Conservative MEP for the South West, added that the virulent H5N1 strain can "spread like wildfire".

He said every time there is an outbreak, more lessons are learnt about how the virus can be contained.

There is no need to panic over the bird flu outbreak, Conservative MEP Neil Parish said.

One of the European Parliament's leading members on bird flu preparations in Europe, and chairman of its Agriculture Committee, Mr Parish commented: "This outbreak has been detected early and action taken swiftly to contain it.

"The EU and Defra have put in place some very stringent procedures to prevent an outbreak from spreading. Of course we must all be vigilant, but there is absolutely no need for panic or hysteria."

A Bernard Matthews spokesman said: "While Bernard Matthews can confirm that there has been a case of H5N1 avian influenza at its Holton site, it is important to stress that none of the affected birds have entered the food chain and there is no risk to consumers.

"Bernard Matthews is working closely with Defra and other industry bodies to contain the infection. The company meets and in many cases far exceeds Defra's biosecurity standards for combating avian flu."